US Defense Secretary Donald H.Rumsfeld told Congress Friday that he takes "full responsibility"for the abuse of Iraqi prisoners by American soldiers,but said hewould not resign as called by Democrats and several newspapers.

"These events occurred on my watch.As secretary of defense,Iam accountable for them,and I take full responsibility,"Rumsfeldsaid in opening remarks at separate hearings at the Senate and House Armed Services Committees.

Rumsfeld apologized for failing to treat Iraqi detainees right."Our country had an obligation to treat them right.We didn't,andthat was wrong.So to those Iraqis who were mistreated by members of the US armed forces,I offer my deepest apology,"Rumsfeld said.

The defense secretary acknowledged that the scandal has caused damage to the US armed forces,the President,the Congress and theAmerican people."And finally to the reputation of our country,"he added.

Rumsfeld outlined measures the Pentagon is taking to deal with the problem.He said he would announce the appointment of several senior former officials to examine the existing investigations andto report their findings within 45days.

Rumsfeld was grilled by Congress as the growing abuse scandal threatens to cause permanent damage to US images in the world,especially the Middle East region,and to weaken domestic support for the US occupation of Iraq.

The defense secretary has been under withering fire for his handling of the scandal.Prominent Democrats,including presidential candidate John Kerry and House Minority Leader Nancy Pelosi,has demanded his resignation,accusing him of cover-up since the start of the problem.

The New York Times,one of several newspapers calling for Rumsfeld's resignation Friday,said in an editorial that "it is time now for Mr.Rumsfeld to go,and not only because he bears personal responsibility for the scandal of Abu Ghraib.That would certainly have been enough."

Senior Republicans also fumed over Rumsfeld's failure to alert them to the brewing crisis.

At the Senate hearing,Rumsfeld acknowledged that it was "possible"that his resignation would help demonstrate how seriously the United States take the situation,and therefore helpto undo some of the damage to its reputation.

But he insisted that he would not resign under political pressure,saying the only factor in his decision is whether he canstill be effective as defense secretary.

"Certainly since this firestorm has been raging,it's a question that I've given a lot of thought to,"Rumsfeld said."Thekey question is ...whether or not I can be effective."

"Needless to say,if I felt I could not be effective I'd resign in a minute.I would not resign simply because people try to make a political issue out of it,"Rumsfeld said.

President George W.Bush rejected calls for the resignation ofRumsfeld on Thursday,saying he is "a really good secretary of defense."

It is too early to tell if Rumsfeld's testimony would help easethe anger of the Arab world.His testimony was broadcast live by two major Arabic television networks.

Kerry quickly dismissed Rumsfeld's apology,saying Bush shouldtake full responsibility for it."The chain of command goes all the way to the Oval Office,"he told the Democratic Leadership Council in Phoenix.

Kerry again called for the resignation of Rumsfeld,saying Bushshould be replaced also."America does not merely need a new secretary of defense.We need a new president,"he said.

As the Bush administration is trying to depict the scandal as isolated events,the International Red Cross said Friday it had warned Washington of abuse of prisoners in Iraq more than a year ago and the problem was "a broad pattern,not individual acts."

The firestorm started last week when photographs showing smirking American soldiers,male and female,sexually humiliating Iraqi prisoners in Iraq.Those pictures cause widespread rage in the Arab world.

Adding new fuel to the boiling scandal,The Washington Post on Thursday published new graphic images providing more damaging evidence.One picture on the front page showed a US woman soldier holding a leash tied around the neck of an Iraqi man,who is naked,grimacing and lying on the floor.

Rumsfeld disclosed at the hearings that there were many more photos and videotapes related to the scandal."There are a lot more photographs and videos that exist,"he said."If these are released to the public,obviously it's going to make matters worse."